Many people still think that in the reproductive war, sperm must be involved in "swimming sprint" towards the egg. Only the fastest and most powerful ones successfully combine to form embryos.
However, the truth seems quite the opposite.
In women when they reach puberty, the ovaries will produce about 300,000 egg cells. But throughout their lives, only about 400 cells develop into eggs and fall. Considering that, the rate of oocytes transformed into eggs is about 0.13%.
99.87% of all egg cells are still only cells.
An estimated average life of a person exported about . 2000 billion sperm.
In men, an average life of one person is estimated to be about . 2000 billion sperms. If 99.87% of egg cells never used in women are wasteful, this is called super waste. Because only 1/250 million sperms (once average ejaculation) are likely to successfully conquer the entire "swimway". Ie only occupied 0.00000004%.
"Fierce" competition is like that, but in fact the sperm battle is strange.
Common fertility routines say that, as soon as "landed", the entire sperm rushed to rush into the swimming speed of the position of the egg. Only the fastest, healthiest baby will have the opportunity to combine with eggs, forming embryos.
However, reproductive studies in mammals suggest that the oviduct and uterus sperm support movement by contracting, creating thrust. The larger the mammal, the shorter the length of the sperm. Thanks to the short, they save their strength and facilitate the passage of their female genitals and access the eggs.
People are actually a mammal. Although as soon as it was liberated into the female body, the entire sperm was confronted with a hostile acid environment, forced to run right into the cervix to escape the "dead body" . But the impulse just came here.
The uterine wall has many small niches, allowing sperm to rest comfortably, without racing.
On the cervical wall of the female genitals there are many small "caves", each containing about 200,000 sperm . They can leisurely take a rest there for a few days, a boring design and then continue to swim into the womb.
In the womb, the sperm prepared for the swim beyond the most difficult obstacle. They were forced upstream into the fallopian tube. Often, only a few hundred children are successful "climbing" to this highest position.
At the fallopian tube, the sperm faces the last obstacle to the sticky surface, sticking it to the wall of the tube. Come here, it is true that the child is the best, he has the ability to "finish" the most.
In the past, it was thought that sperm could only live for about 2 days in the female genital system.In fact, they can live for more than 10 days.
Fertility routines also say that the more sperm, the stronger the chance, the higher the chance of fertilization. The actual survey also showed that if men can only export less than 100 million sperms / time, the pregnancy rate of women decreases.
Not as much as possible.
But in fact, if the sperm count is too crowded and healthy, it will lead to catastrophic consequences. Because the genitals of the female genitalia will not be able to control the face, eventually to "extract" more than 1 sperm into the egg.
In the case of two sperms combined with one egg, Polyspermy (polyspermy connecting one egg) will occur. Instead of 1 egg + 1 sperm = 46 pairs of sex chromosomes, it turns into 1 egg + 2 sperm = 69 pairs, leading to miscarriage or death after birth.
Similar to the case on 2 sperm combined with 1 egg. Therefore, when artificial insemination, because of direct sperm injection into the uterus, people are limited to about 20 million units. Particularly, in vitro fertilization, it is only down to 25 thousand.
And although men produce less than 100 million sperms per time, the pregnancy rate of women decreases, but over 100 million / time does not matter.